By definition, he can't be easy to study if you can't gain access to the majority of his best work.
For instance, Seth Raynor must surely be the worst. Tillinghast is a nightmare too, save for Bethpage. Crump and Fownes aren't exactly easy
Is Pete Dye the answer (I am posting this from America and I realize that the answer would be different for someone in the UK or Australia)? Casa de Campo, Ocean Course at Kiawah, his courses in Kohler, Harbor Town, TPC Stadium, Sadly The Golf Club wouldn't be among them but that's only one.
Who else? I would say NOT Ross as access to Salem, Essex County, Charles River, Wannamoisett, Plainfield, Metacomet, Beverly, Highlands, etc. are not readily available and yet such courses are crucial to gain a fuller understanding from just his Pinehurst work.
A sad problem
in living in Australia is that the easiest architect to study is MacKenzie - some folks get all the luck!